1. Astrid Lindgren Children's Hospital, Karolinska University Hospital and Department of Women's and Children's Health; Childhood Cancer Research Unit, Karolinska Institutet; Stockholm Sweden
2. Department of Radiology; Helsinki University Hospital; Helsinki Finland
3. Department of Paediatrics and Adolescent Medicine; The University Hospital Rigshospitalet; Copenhagen Denmark
4. Children and Adolescents Hospital; Helsinki University Hospital; Helsinki Finland
5. Department of Pediatrics; Sahlgrenska University Hospital; Gothenburg Sweden
6. Department of Children and Adolescents; Oulu University Hospital; Oulu Finland
7. Faculty of Medicine; The Institute of Gynecology, Obstetrics, and Pediatrics, University of Copenhagen; Denmark